Low thermal shrinkage separator and a method for manufacturing thereof

Abstract

A low thermal shrinkage separator and a method for manufacturing thereof are disclosed. The method comprises providing a porous polyolefin substrate with a plurality of porous structures on the surfaces and interiors thereof, and applying a precursor solution comprising a titanium alkoxide and a photo-reactive agent, and subsequently irradiating by a UV light to form a low thermal shrinkage thin layer on the surface of the porous polyolefin substrate and the interior sidewalls of the porous structures of the porous polyolefin substrate. The present method can enhance the low thermal shrinkage and electrolyte wettability of the separator.

What is claimed is: 
     
         1 . A method for manufacturing a low thermal shrinkage separator, comprising the steps of:
 providing a porous polyolefin substrate with a plurality of porous structures on surfaces and interiors thereof;   applying a precursor solution containing 0.1 wt % to 3.0 wt % titanium alkoxide and 0.05 wt % to 1.0 wt % photo-reactive agent to the porous polyolefin substrate; and   irradiating by a UV light with a radiation dose of 10 mJ/cm 2  to 1000 mJ/cm 2  to form a low thermal shrinkage thin layer on a surface and sidewalls of the porous structures of the porous polyolefin substrate.   
     
     
         2 . The method as claimed in  claim 1 , wherein the titanium alkoxide of the precursor solution is titanium methoxide, titanium ethoxide, titanium isopropoxide, titanium tert-butoxide, or combinations thereof. 
     
     
         3 . The method as claimed in  claim 2 , wherein the titanium alkoxide of the precursor solution is titanium isopropoxide. 
     
     
         4 . The method as claimed in  claim 1 , wherein a solvent of the precursor solution is methanol, ethanol, isopropanol, or combinations thereof. 
     
     
         5 . The method as claimed in  claim 1 , wherein the precursor solution contains a 0.1 wt % to 2.0 wt % titanium alkoxide. 
     
     
         6 . The method as claimed in  claim 1 , wherein the photo-reactive agent is 2-isopropylthioxanthone, thioxanthone, thioxanthone derivatives or combinations thereof. 
     
     
         7 . The method as claimed in  claim 1 , wherein the precursor solution contains a 0.05 wt % to 0.8 wt % photo-reactive agent. 
     
     
         8 . The method as claimed in  claim 1 , wherein the porous polyolefin substrate is a single-layered or multi-layered porous polyolefin substrate of polyethylene, polypropylene or copolymers thereof obtained by dry-stretching. 
     
     
         9 . The method as claimed in  claim 1 , wherein the precursor solution is applied by dip coating or spray coating. 
     
     
         10 . A low thermal shrinkage separator, comprising:
 a porous polyolefin substrate with a plurality of porous structures on surfaces and interiors thereof; and   a low thermal shrinkage thin layer formed on the surface and the sidewalls of the porous structures of the porous polyolefin substrate;   wherein the low thermal shrinkage thin layer is a composite thin layer of cross-linked titanium alkoxide, photo-reactive agent, and hydrogen-containing carbon chains of the surfaces and the sidewalls of the porous structures of the porous polyolefin substrate.